Asian Elm tree inner bark prevents articular cartilage deterioration in ovariectomized obese rats with monoiodoacetate-induced osteoarthritis.

We investigated whether long-term consumption of Korean mistletoe or Asian Ulmi cortex would prevent or delay menopausal symptoms and progression of osteoarthritis in estrogen-deficient obese rats.

Ovariectomized (OVX) rats were provided a 45% fat diet containing either (1) 0.6% lyophilized water extract of Korean mistletoe (KME) + 1.4% dextrose (KME; n = 10), (2) 2% lyophilized water extract of Ulmi cortex (UCE; n = 10), (3) 30 μg/kg bw 17β-estradiol + 2% dextrose (positive control; n = 10), (4) 2% dextrose (placebo; OVX-control; n = 10), or (5) 2% dextrose (normal-control; n = 10) for 4 weeks. At the beginning of the 5th week, OVX rats, except in the normal-control group, were given articular injections of monoiodoacetate into the right knee and the assigned diets were provided for an additional 3 weeks. The rats in the normal-control had injections of saline into the right knee.

KME, but not UCE, partially prevented the insulin resistance and the loss of bone mineral density and lean mass. The limping scores were lower in the descending order of the OVX-control > KME and 17β-estradiol > UCE > normal-control at day 14 and 21 (P < 0.05). The scores for pain behaviors measured by weight distribution on the right leg, maximum running velocity on a treadmill and locomotive activity, were markedly decreased in the same order as limping scores. Monoiodoacetate increased the expression of matrix metalloprotinase-3 and metalloprotinase-13 in the articular cartilage and elevated the production of inflammatory markers such as tumor necrosis factor-α, interleukin-1β, and interleukin-6, but they were lower in the UCE than in the other groups (P < 0.05). Histology of the right knee revealed cartilage damage near the tidemark of the knee and proteoglycan loss was markedly less in UCE.

UCE was an effective therapeutic agent for preventing osteoarthritis and KME prevented decreases in lean body mass, bone mineral density, and insulin sensitivity in estrogen-deficient rats.